<!doctype html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport"
          content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <script src="https://cdn.jsdelivr.net/npm/vue@2.6.10/dist/vue.js"></script>
    <title>Document</title>
</head>
<body>
    <div id="app">
        <button @click="fullName='li xiaoxiao'">change</button>
        <h2>全名是 {{fullName}}</h2>
        <h2>全名是 {{fullName}}</h2>

    </div>
    <script>

        Vue.config.productionTip = false

        const vm = new Vue({
            el:'#app',
            data(){
                return{
                    firstName:'MEI',
                    lastName:'QINGJUN'
                }
            },
            computed:{
                fullName:{
                  get(){
                      console.log('getter');
                      return(
                          this.firstName.toLowerCase() + '' + this.lastName.toLowerCase()
                      )
                  },
                  set(val){
                      console.log('setter', val)
                      this.firstName = val.split(' ')[0];
                      this.lastName = val.split(' ')[1]
                  }
                },

            }
        })
    </script>
</body>
</html>